
bt.module({builder: function(bt) {
    var TOTLE = 3;
    var current = TOTLE - 1;
    var interval = 5000; //ms
    var timer;
    var _changePosterBg = function() {
        j$(".poster .poster-bgs .bg" + current).fadeOut(
            function() {
                current = (current + 1) % TOTLE;
                j$(".poster .poster-bgs .bg" + current).fadeIn();
            });
        timer = setTimeout(function() {
            _changePosterBg();
        }, interval);
    };

    j$(document).ready(function() {
        _changePosterBg();
    });

}});
